A speech recognition apparatus has been so far used for recognizing words contained in a speech spoken by an unspecified speaker to output the words as text data.
PUPA 06-12483, PUPA 08-50493 and PUPA 09-22297 (references 1-3), for example, disclose such speech recognition methods.
For example, when English text data is generated from an English speech spoken by a Japanese speaker by an English speech recognition apparatus for recognizing English words from an English speech using a conventional speech recognition method, the recognition rate is low. This is because English language contains a sound which does not exist in Japanese language (th, etc.) or a sound which is difficult to be discriminated in Japanese language (l, r, etc.) and Japanese speaker are not generally capable of pronouncing such English sound correctly so that the English speech recognition apparatus translates an incorrect pronunciation into a word as it is. For example, even when a Japanese speaker intends to pronounce "rice" in English, the English speech recognition apparatus may recognize this pronunciation as "lice" or "louse".
Such inexpediences may occur in various situations such as when an American whose native language is English uses a speech recognition apparatus for generating a Japanese text from a speech in Japanese contrary to the above, when a British speaker whose native language is British English uses a speech recognition apparatus tuned for American English, or when a particular person has a difficulty to pronounce correctly by some reason.
The speech recognition apparatus disclosed in the above references, however, are unable to solve such inexpediences.
If English pronunciation of the speaker is improved approaching a pronunciation of a native speaker, the recognition rate of the speech recognition apparatus is naturally improved and it is in fact desirable for a speaker to improve English conversation.
For example, PEPA4-54956 discloses a learning apparatus for recognizing English speech of a speaker and causes the speaker to affirm the recognized English speech (reference 4).
Also, PUPA60-123884, for example discloses an English learning machine for letting the speaker listen to a speech to learn by using a speech synthesizer LSI (reference 5).
A learning apparatus for learning pronunciation of foreign language is disclosed in many other publications including PEPA44-7162, PEPA H7-117807, PUPA61-18068, PEP H8-27588, PUPA62-111278, PUPA62-299985, PUPA3-75869, PEPA6-27971, PEPA8-12535, and PUPA3-226785 (references 6 to 14).
However, the speaker can not necessarily attain a sufficient learning effect using the learning apparatuses disclosed in these references because the speaker has to compare his or her own pronunciation with a presented pronunciation or he or she fails to find which part of his or her pronunciation is wrong.